Avionics News October 2015 - 35

A member of the Peregrine team
conducts ground tests on a Trig ADS-B STC
installation in a Cessna 172.
Photo courtesy of Peregrine

and transponder is working as it should until you get into the
inner workings of the systems."
And that's why ADS-B requires an STC. "Once we've proven
that a Garmin GTN 650 and Trig TT31 1090 ES transponder,
when wired this way and connected to this antenna meets all the
requirements, it will replicate those performance requirements if
you follow the STC instructions," Davis explained.
When it comes to installations that require an STC, the process that proves a combination meets the required performance
parameters "is not our specialty," Davis said. "There would be a
huge learning curve in doing it ourselves. It's far easier, quicker,
efficient and economical to partner with a company that already
possesses the knowledge and experience necessary to earn FAA
supplemental type certificates and build its approved model list."
Nodding at Peregrine CEO David Rankin, Davis said, "We
met at the AEA Convention several years ago."
Since then, Peregrine has earned three ADS-B Out STCs that
integrate Trig's TT31 and TT22 1090 ES transponders with a
number of different GPS/WAAS position sources, including the
full range of Garmin's GNS and GTN GPS/WAAS navigators.
The TT31 is a plug-and-play replacement that employs the existing trays for the BendixKing KT 76A and KT 78A transponders,
and the STC's make and model list covers 650 aircraft, from
Aermacchi to Zlin.
The Trig TT22, a remote-mounted 1090 ES transponder, has
two STCs. Drawing on the same position sources, its AML lists
576 aircraft, from Aermacchi to Viking Air Limited's DHC-3

Otter. The second TT22 STC combines it with a FreeFlight
Systems 1201 GPS/WAAS position sensor in Sikorsky S-76
helicopters.
As the applicant, Peregrine owns the STCs, and it works
closely with the Trig dealer network. "They contact us for the
STC paperwork and questions" related to putting the boxes in
the airplane and configuring the system, Rankin said. The STC
includes thorough documentation, followed up with updates as
needed.
The STC process involves ground and flight tests, Rankin
explained. Installing the Trig transponders with the variety of
GPS/WAAS position sources in every aircraft on the AMLs
would be impossibly expensive and time consuming. Instead,
Peregrine installs the ADS-B system in representative aircraft
made of metal and composites that have wings high and low and
landing gear that is fixed and retractable and then extrapolates
the engineering data.
The FAA asked the partners to test an airplane with a fabriccovered welded-steel fuselage, Davis interjected. "We used a
Pitts Special, and the FAA asked if we'd add aerobatics to the
flight test, and ADS-B Out works in all attitudes." Looking
at the ATC position, speed and altitude data, inverted flight is
indistinguishable from straight and level, "but you can see loops,
rolls, hammerhead turns and other maneuvers that are anything
but straight and level."
Continued on following page
avionics news

october

2015

Table of Contents for the Digital Edition of Avionics News October 2015